Natural gas, as is well known, is a mixture of low molecular weight, paraffin hydrocarbons which typically comprises at least 85% methane, and more typically 90% or more of methane. It is a colorless almost odorless gas which is used as a common industrial fuel, as a cooking gas, as a heating gas, and the like. Primary source of natural gas is from natural degradation of organic materials by heat and pressure in the earth. Large caverns of natural gas exist within the earth and typically exist immediately above oil pools.
The natural gas must be transported from its source in the earth to its ultimate end use point. Quite naturally, since natural gas is a gas its volume is quite large and its transportation very difficult in its gaseous state. As a result, transportation of natural gas from its source to its point of usage has been a difficult problem. The problem has been approached in many different manners. One of the more common is to place the natural gas under extreme pressure to liquefy the natural gas and ship it in tanks. However, of course, the use of additional energy and additional expense is necessitated by the pressurization process.
Another means of attacking the problem has typically been to liquefy the natural gas at extremely low temperatures and to transport the liquefied natural gas in refrigerated units at such low temperatures. For example, natural gas, at ambient pressure, will liquefy at minus 270.degree. F. In this manner of shipping of natural gas from its source, extremely large refrigeration units, for example, refrigeration ships, have been built at extreme cost to transport the liquefied natural gas from its source to its point of designated usage. In spite of the extreme cost of such ships, this method of transportation is much more efficient than transporting the gas in its gaseous state since substantially greater quantities can be transported per given unit of volume.
Still, as one can well imagine, it is extremely expensive to provide the energy for such large transportable refrigeration units. Therefore, a significant savings of energy and correspondingly a significant savings of cost of natural gas, could be provided if the need for excessively large transportable refrigeration units could be eliminated.
Accordingly, one object of this invention is to provide a method of transporting natural gas which does not require ultra low temperature refrigeration units.
Another object of this invention is to provide a method of transporting natural gas which eliminates the need for refrigeration units which can refrigerate natural gas to temperatures as low as minus 270.degree. F.
Yet another object of this invention is to provide a method of transporting natural gas which utilizes substantially lesser quantities of energy for refrigeration of the natural gas during transport.
A still further object of this invention is to provide a method of transporting natural gas which allows liquefication of natural gas, at atmospheric pressure, at temperatures as high as minus 50.degree. F.
Another object of this invention is to provide not only a method of transporting natural gas at substantially higher temperatures than utilized in the past, but also of increasing the Btu capacity of the transported natural gas.
The method of accomplishing these and other objects of the invention will become apparent from the following detailed description of the invention.